In recent years, substances toxic to living bodies, such as environmental pollutants, carcinogenic substances, and endocrine disruptive (chemical) substances, are posing a significant global issue. There are concerns that these toxic substances may affect living bodies through breast milk or commercially sold milk. The influence these extrinsic toxic substances may have on living bodies could be clarified if it becomes possible to collect milk from laboratory animals, such as rats or mice, in a simpler way.
However, because relatively small and prolific laboratory animals such as rats and mice have small teats and produce only small amounts of milk, no effective milking apparatuses for these animals have been proposed. For example, it is difficult to obtain the milk of rats directly from their teats, and, therefore, in locations such as laboratories, the milk is normally collected from the stomach of a newborn rat that has been fed. The milk collected from the stomach, however, could have had its milk components broken down or digested through mixing or stirring with saliva and gastric fluid, and it is questionable if such milk could be considered true milk.
In response to these needs, the present inventor had already developed an improved milking apparatus capable of milking directly from the udder of a rat or a mouse, and a teat cup therefor, and had filed an application therefor (Patent Document 1 and Patent Document 2). This milking apparatus enables even a single experimenter to perform a milking operation on a laboratory animal, thereby allowing for the acquisition of universal milking data that is not subject to individual differences between experimenters.
Patent Document 1: Domestic Re-publication of PCT International Publication (“kohyo”) WO 01/067064
Patent Document 2: JP Patent Publication (Kokai) No. 2005-130774 A